Grand Canyon

The Grand Canyon is so named because the Colorado River has over time cut through an expansive and very scenic canyon for many miles in the Arizona desert. The Grand Canyon plays a critical role in this book as the object of Powell's curiousity, and as the expedition that launched his long and distinguished career in the American government. The land and water use principals forwarded by Powell for this area are in use today.

Science of Man

This is a term used by the author to differentiate between the interests of Powell that included the sciences of humans, languages, culture, etc., and not sciences of the earth like geology.

Geology

This is the study of the earth's surface. Geology and geography were the center of Powell's work as he planned his expedition down the Colorado River.